Problem: $\dfrac{8}{2} - \dfrac{3}{10} = {?}$
Explanation: $ = {\dfrac{8 \times 5}{2 \times 5}} - {\dfrac{3 \times 1}{10 \times 1}} $ $ = {\dfrac{40}{10}} - {\dfrac{3}{10}} $ $ = \dfrac{{40} - {3}}{10} $ $ = \dfrac{37}{10}$